Cotton Shorts, Short Tank Tops, Tank Tops, Cotton Shirts: NPCs could stop selling these items and players could stop being rewarded with them using monster points. This would increase their value and give more purpose for going on mouboo hunting quests. Repairing/extending cotton items could require bleaching and then re-dyeing. This could replace the ease of acquiring clothing and make it more of a selling item.

Chain mail, Light Plate, Warlord Plate: Get rid of "Blacksmith", make "Nicholas" the only blacksmith. He could create: Chain mail at 20,000 gp + 5 ore, Light Plate at 50,000 gp + 10 ore and Warlord Plate at 100,000 gp + 20 ore. Ore is still valuable on the market with the current set up, but Warlord Plate is harder to buy and sell because of its fixed purchasing price.

If I buy Warlord Plate to sell as a merchant, the most I could hope for is to trade the Warlord for a variety of items with a reduced cost. The number of commodity items needed to compensate for 100k is usually larger than a buyer can extend in a trade when they could just sell their items and buy the armors from the NPC.

It is also easier to sell items as a player merchant when a player merchant can offer pure gold piece prices versus the NPC that is only using the gp to help with materials not listed in the creation of the item.